0:00

These are images of a four-year-old boy

0:03

who's presenting with ankle pain and

0:06

inability to bear weight on that extremity.

0:10

On T1-weighted images, there is replacement of

0:14

the normal T1-bright fatty marrow in the epiphysis

0:20

of the distal tibia with associated diffuse

0:24

marrow edema noted on fluid-sensitive sequences.

0:27

There is reactive change in the marrow also across

0:31

the joint space at the level of the pillar body.

0:36

In addition, there is an associated joint effusion

0:41

with distention of the anterior and posterior

0:45

joint recesses, outlining punctate hypointensities

0:50

foci in keeping with intraarticular debris.

0:55

In the setting of pain, inability to

0:58

bear weight, the main differential

1:01

diagnosis is that of septic arthritis.

1:05

Aspiration of the fluid is indicated

1:08

to assess for the presence of bacteria

1:13

on fluid analysis and cultures.

1:16

The differential diagnosis

1:18

would be with inflammatory,

1:21

rheumatoid arthritis, juvenile rheumatoid

1:23

arthritis, and the fluid analysis will be

1:27

crucial in order to make that distinction.

Wk 3, Case 4 - Review

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0:00

These are images of a four-year-old boy

0:03

who's presenting with ankle pain and

0:06

inability to bear weight on that extremity.

0:10

On T1-weighted images, there is replacement of

0:14

the normal T1-bright fatty marrow in the epiphysis

0:20

of the distal tibia with associated diffuse

0:24

marrow edema noted on fluid-sensitive sequences.

0:27

There is reactive change in the marrow also across

0:31

the joint space at the level of the pillar body.

0:36

In addition, there is an associated joint effusion

0:41

with distention of the anterior and posterior

0:45

joint recesses, outlining punctate hypointensities

0:50

foci in keeping with intraarticular debris.

0:55

In the setting of pain, inability to

0:58

bear weight, the main differential

1:01

diagnosis is that of septic arthritis.

1:05

Aspiration of the fluid is indicated

1:08

to assess for the presence of bacteria

1:13

on fluid analysis and cultures.

1:16

The differential diagnosis

1:18

would be with inflammatory,

1:21

rheumatoid arthritis, juvenile rheumatoid

1:23

arthritis, and the fluid analysis will be

1:27

crucial in order to make that distinction.

Report

Patient History
4-year-old patient with no known injury complaining of right ankle pain and inability to bear weight.

Findings
SKELETAL/BONES:
Marked diffuse edema throughout the distal tibial chondral epiphysis with extensive surrounding soft tissue inflammation (loss of the normal apophyseal hyperintensity). Low-grade osteoedema through the distal tibial metaphysis. Diffuse intermediate-grade osteoedema throughout the talus, predominantly around the tibiotalar articulation. Marked diffuse high signal tibiotalar capsulosynovial thickening associated with a complex effusion.

Low-grade osteoedema through the plantar calcaneus.

Preservation of the cortical outline (no cortical destruction/dehiscence). No subperiosteal fluid collection.

No micro- or macro-trabecular fracture.

ARTICULATIONS:
Tibiotalar joint/talar dome: Complex tibiotalar effusion with particulate debris. Extensive capsulosynovial thickening.

Ankle mortise/syndesmosis: The ankle mortise is in anatomic alignment. No syndesmotic widening.

Chopart joint: Unremarkable.

Midfoot/hindfoot: Unremarkable.

Lisfranc joint: The Lisfranc joint is intact, without fracture or joint space widening.

LIGAMENTS:
High ankle: Intact. Diffuse reactive edema extending along the interosseous membrane.

Low ankle: Intact.

Subtalar/Chopart: Intact.

TENDONS:
Reactive tenosynovial thickening involving the posterior tibial tendon and flexor digitorum longus at the level of the joint. No tenosynovial effusion.

GENERAL:
Sinus tarsi: Unremarkable.

Muscles: Diffuse muscle edema of the distal tibialis posterior.

Soft tissue: Extensive soft tissue swelling centered around the tibiotalar articulation.

Plantar fascia: Intact.

Neurovascular complex/tarsal tunnel: Unremarkable. No evidence of entrapment neuropathy.

Intra-articular/loose bodies: None.

Impressions
1. Acute or subacute inflammatory tibiotalar arthritis (favoring septic arthritis, or less likely JIA or juvenile idiopathic arthritis with a developing area of avascular necrosis involving the tibial epiphysis). Tibiotalar capsulitis with associated complex effusion containing particulate debris (possibly purulent). Regional myositis (tibialis posterior). No intraosseous, subperiosteal or soft tissue abscess.
2. Recommend joint aspiration and analysis.

Case Discussion

Faculty

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

Jenny T Bencardino, MD

Vice-Chair, Academic Affairs Department of Radiology

Montefiore Radiology

Edward Smitaman, MD

Clinical Associate Professor

University of California San Diego

Practice Cases

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Practice Cases

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Wk 3, Case 4 - Review